<script type="text/javascript">
//写cookies函数
function SetCookie(name, value)//两个参数，一个是cookie的名子，一个是值
{
var Days = 30; //此 cookie 将被保存 30 天
var exp = new Date(); //new Date("December 31, 9998");
exp.setTime(exp.getTime() + Days * 24 * 60 * 60 * 1000);
document.cookie = name + "=" + escape(value) + ";expires=" + exp.toGMTString();
}

function getCookie(name)//取cookies函数
{
var arr = document.cookie.match(new RegExp("(^| )" + name + "=([^;]*)(;|$)"));
if (arr != null) return unescape(arr[2]); return null;

}

function delCookie(name)//删除cookie
{
var exp = new Date();
exp.setTime(exp.getTime() - 1);
var cval = getCookie(name);
if (cval != null) document.cookie = name + "=" + cval + ";expires=" + exp.toGMTString();
}

SetCookie('Time', '30');

alert(getCookie('Time'));

</script>